Tipaimukh Dam: its nuts and bolts need dovetailing
The controversial Tipaimukh Dam in the southwest of Manipur that India is planning to build faces severe criticism in Bangladesh as well as in India itself because of environmental and a host of other reasons. In the second part of the three-part article, Abdul Mannan discusses some pertinent issues with regards to the project.
Fulertal Barrage: The issue is still indiscreet. Very little details are so far known. Neither its aims nor the objectives have been made clear. The Barrage is 100 km (app.) downstream diagonally of Tipaimukh Dam and 100 km diagonally upstream of Amalshid in Sylhet. It is apprehended that India may regulate water flow at the Dam and then divert it to the Fulertal Barrage, thus having direct bearing on the flow of Surma, Kushiyara and Meghna rivers invariably affecting total ecosystem in all spheres for the 1/3 area of Bangladesh.
Earthquake risks: In the N-E regions earthquake risks zone i.e. Surma Basin, major events are controlled by Dauki Fault system i.e. zone 1 comprising NE region of Bangladesh. With the presence of Dauki Fault system of Eastern Sylhet and the deep seated Sylhet Fault and proximity to the Jaflong Thrust, Naga Thrust and Disang Thrust, it is a zone of high seismic risk with a basic co-efficient of 0.08.
Geographic and topographic features at Tipaimukh and adjoining areas are noteworthy due to drainage pattern of Barak river and structural and tectonic lineaments of the region. Moreover, the main Barak river opposite to Tuivai river is also controlled by Barak-Makru Thrust Fault. Barak river course and its tributary system are controlled by faults and fractures causing localised shifting and deflection of main river course rendering such faults as potential focal or epicentres of earthquakes.
Thus, having considered the issue of high seismic risk with basic co-efficient of 0.08, past records of earthquakes in the region over last 200 years, the volume and weight of water containment up the Dam at 16 m cu m and weight load of rocks of the Mega Dam at 25 m MT (app.), Tipaimukh Dams axis falling on a fault line likely to be the epicentre, an earthquake of 7 plus Richter Scale dimension will play havoc with the load and onrush of 16 m cu m water of the reservoir followed by heavy rush of upstream water and weight load of 25 m MT rocks frictioned to pieces, up and down, rushing towards Bangladesh at great speed and thus, posing as a serious threat.
Impacts of the mega dam at Tipaimukh
(i) Tipaimukh Dam without operation of Fulertal Barrage: It means supposedly no withdrawal of water up or downstream before the flow enters Bangladesh border. Based on the theory of constancy, the water flow quantity for the year as a whole will not fluctuate much. But variation will occur season wise specially due to the controlled and regulated release of water through the turbines and spillway gates. Thus, the age-old natural flow of the river water will turn into an unnatural one.
The following issues are needed to be borne in mind here:
a. the situation at a hydropower generation of 412 MW (most likely generation will be kept at 412 MW until Fulertal Barrage goes into operation and starts withdrawal of water downstream of the Dam).
b. the situation at generation of hydropower of 1200 MW (80 per cent of 1500 MW).
c. Season i.e. rain falls in monsoon, post monsoon and winter periods.
Scenario I(A):- Only dam and no barrage. (at a hydropower generation of 412 MW)
Monsoon period: Water level will be maintained up the Dam point reservoir utilising excess water of the monsoon rainfalls giving an effect of less water flow to Bangladesh than normal flow Bangladesh experiences now during the monsoon. Excessive rainfalls may cause release of more water through the spillway gates. Water will pass through the Dam downstream in two ways i.e. through the turbines after generation of hydropower and excess water from the reservoir up the Dam through the spillway gates. Obviously, there is bound to be siltation of rivers downstream in Bangladesh.
Post monsoon period: Due to global climate change (e.g. CFC emission etc.) distortion in the pattern of rainfalls has been taking place resulting into excess rainfalls at the end of monsoon and will necessitate release of excess water through the spillway gates of the Dam and may create unusual and unnatural off-monsoon floods in Bangladesh. Thus the wetlands of Surma-Kushiayara basin will experience waterlogged, water holds, rendering the wet land unsuitable for early cultivation which hitherto the people of this area have been doing from time immemorial. Hence, there will be less or no crops.
Winter period: The level of water at the reservoir up the Dam and level of turbine operation for hydropower generation of 412 MW are likely to have a little more quantity of water than we are set now in the winter, but much will depend upon release of water through the turbines and, if any, through the spillway gates. However, we cannot afford to turn blind eye to an opposite scenario, when we may have less water, even in winter, due to any make-up filling of water in the reservoir up the Dam and the level of operation of the turbines.
The basic issue here is that flow pattern will change due to manmade dam disrupting God-made natural flow. In a nutshell, to obtain our legitimate share of water flow, we shall have to depend upon the mercy of the Indian authority who will control and regulate the flow through the Dam.
Regulated flow entailing change in the pattern of flow will do a lot of harm due to:
Reduction in agri-crops, loss in navigability, less water availability, siltation of river beds, off-season floods, dwindlement of fisheries, lower ground water with more arsenic contamination and as a whole Bangladesh will undergo a total adverse change in pattern of the ecosystem.
Scenario I(B): The scenario here is as that of I(A) above except that hydropower generation will be for 1200 MW.
The situation is likely to be similar to that of I(A), (a), (b) and (c) above with perhaps, more variation in pattern of flow due to maintenance of level of water in the reservoir up the Dam, more variation in releasing water through the turbines and spillway gates.
Scenario II: Operation of the Dam and the Fulertal Barrage through withdrawal of water at downstream of the Dam. (Here it has been assumed that hydropower generation will be to the level of 1200 MW involving maintenance of higher level of water in the reservoir up the Dam.)
Monsoon period: Heavy withdrawal of water coming out at the turbines as well as spillway gates will be diverted at downstream of the Dam to the Fulertal Barrage leaving little share of the water flow for Bangladesh. Hence there will be reduction in water flow for Bangladesh. Only very unusual and heavy rainfalls uncontainable and unmanageable at the reservoir up the Dam also imposing at the Fulertal Barrage a threat towards floods, an increase water flow will be released towards Bangladesh causing havocs of floods.
Post-monsoon period: Depending upon rainfalls, manageability of water level at the Dam as well as that at the Barrage, our wetlands of the Surma/Kushiyara Basin may be exempted from excess water i.e. no water-holds thus enabling early cultivation. However, unnatural and heavy rainfalls may reverse the situation and cause formation of water-holds in the haor areas.
Winter period: Heavy withdrawal upstream for the Fulertal Barrage may leave little or nothing for Bangladesh at the downstream. Literally, 1/3 Bangladesh is likely to go under the process of desertification ensuing a total collapse for 1/3 of Bangladesh.
Adverse effects upon various areas and disciplines like agriculture, fisheries, water resources, navigability, ground water level, livelihood etc. have been highlighted earlier. These will need minor adjustments here and there for different scenarios mentioned above.
Generation of Hydropower: The capacity designed is 1500 MW @ 80 per cent = 1200 MW (assumed). But the proposed firm generation set at only 412 MW is more intriguing.
Of the expected generation of 412 MW, Manipur has been offered 40 MW free to appease the people there. Thereafter how much India can afford to sell to Bangladesh and at what price, inclusive of the installation of transmission line up to the border and absorption of its cost in the price, needs to be looked at with a grain of salt.
Abdul Mannan is a former lawmaker and state minister for civil aviation and tourism
http://www.newagebd.com/2009/jun/29/oped.html
The controversial Tipaimukh Dam in the southwest of Manipur that India is planning to build faces severe criticism in Bangladesh as well as in India itself because of environmental and a host of other reasons. In the second part of the three-part article, Abdul Mannan discusses some pertinent issues with regards to the project.
Fulertal Barrage: The issue is still indiscreet. Very little details are so far known. Neither its aims nor the objectives have been made clear. The Barrage is 100 km (app.) downstream diagonally of Tipaimukh Dam and 100 km diagonally upstream of Amalshid in Sylhet. It is apprehended that India may regulate water flow at the Dam and then divert it to the Fulertal Barrage, thus having direct bearing on the flow of Surma, Kushiyara and Meghna rivers invariably affecting total ecosystem in all spheres for the 1/3 area of Bangladesh.
Earthquake risks: In the N-E regions earthquake risks zone i.e. Surma Basin, major events are controlled by Dauki Fault system i.e. zone 1 comprising NE region of Bangladesh. With the presence of Dauki Fault system of Eastern Sylhet and the deep seated Sylhet Fault and proximity to the Jaflong Thrust, Naga Thrust and Disang Thrust, it is a zone of high seismic risk with a basic co-efficient of 0.08.
Geographic and topographic features at Tipaimukh and adjoining areas are noteworthy due to drainage pattern of Barak river and structural and tectonic lineaments of the region. Moreover, the main Barak river opposite to Tuivai river is also controlled by Barak-Makru Thrust Fault. Barak river course and its tributary system are controlled by faults and fractures causing localised shifting and deflection of main river course rendering such faults as potential focal or epicentres of earthquakes.
Thus, having considered the issue of high seismic risk with basic co-efficient of 0.08, past records of earthquakes in the region over last 200 years, the volume and weight of water containment up the Dam at 16 m cu m and weight load of rocks of the Mega Dam at 25 m MT (app.), Tipaimukh Dams axis falling on a fault line likely to be the epicentre, an earthquake of 7 plus Richter Scale dimension will play havoc with the load and onrush of 16 m cu m water of the reservoir followed by heavy rush of upstream water and weight load of 25 m MT rocks frictioned to pieces, up and down, rushing towards Bangladesh at great speed and thus, posing as a serious threat.
Impacts of the mega dam at Tipaimukh
(i) Tipaimukh Dam without operation of Fulertal Barrage: It means supposedly no withdrawal of water up or downstream before the flow enters Bangladesh border. Based on the theory of constancy, the water flow quantity for the year as a whole will not fluctuate much. But variation will occur season wise specially due to the controlled and regulated release of water through the turbines and spillway gates. Thus, the age-old natural flow of the river water will turn into an unnatural one.
The following issues are needed to be borne in mind here:
a. the situation at a hydropower generation of 412 MW (most likely generation will be kept at 412 MW until Fulertal Barrage goes into operation and starts withdrawal of water downstream of the Dam).
b. the situation at generation of hydropower of 1200 MW (80 per cent of 1500 MW).
c. Season i.e. rain falls in monsoon, post monsoon and winter periods.
Scenario I(A):- Only dam and no barrage. (at a hydropower generation of 412 MW)
Monsoon period: Water level will be maintained up the Dam point reservoir utilising excess water of the monsoon rainfalls giving an effect of less water flow to Bangladesh than normal flow Bangladesh experiences now during the monsoon. Excessive rainfalls may cause release of more water through the spillway gates. Water will pass through the Dam downstream in two ways i.e. through the turbines after generation of hydropower and excess water from the reservoir up the Dam through the spillway gates. Obviously, there is bound to be siltation of rivers downstream in Bangladesh.
Post monsoon period: Due to global climate change (e.g. CFC emission etc.) distortion in the pattern of rainfalls has been taking place resulting into excess rainfalls at the end of monsoon and will necessitate release of excess water through the spillway gates of the Dam and may create unusual and unnatural off-monsoon floods in Bangladesh. Thus the wetlands of Surma-Kushiayara basin will experience waterlogged, water holds, rendering the wet land unsuitable for early cultivation which hitherto the people of this area have been doing from time immemorial. Hence, there will be less or no crops.
Winter period: The level of water at the reservoir up the Dam and level of turbine operation for hydropower generation of 412 MW are likely to have a little more quantity of water than we are set now in the winter, but much will depend upon release of water through the turbines and, if any, through the spillway gates. However, we cannot afford to turn blind eye to an opposite scenario, when we may have less water, even in winter, due to any make-up filling of water in the reservoir up the Dam and the level of operation of the turbines.
The basic issue here is that flow pattern will change due to manmade dam disrupting God-made natural flow. In a nutshell, to obtain our legitimate share of water flow, we shall have to depend upon the mercy of the Indian authority who will control and regulate the flow through the Dam.
Regulated flow entailing change in the pattern of flow will do a lot of harm due to:
Reduction in agri-crops, loss in navigability, less water availability, siltation of river beds, off-season floods, dwindlement of fisheries, lower ground water with more arsenic contamination and as a whole Bangladesh will undergo a total adverse change in pattern of the ecosystem.
Scenario I(B): The scenario here is as that of I(A) above except that hydropower generation will be for 1200 MW.
The situation is likely to be similar to that of I(A), (a), (b) and (c) above with perhaps, more variation in pattern of flow due to maintenance of level of water in the reservoir up the Dam, more variation in releasing water through the turbines and spillway gates.
Scenario II: Operation of the Dam and the Fulertal Barrage through withdrawal of water at downstream of the Dam. (Here it has been assumed that hydropower generation will be to the level of 1200 MW involving maintenance of higher level of water in the reservoir up the Dam.)
Monsoon period: Heavy withdrawal of water coming out at the turbines as well as spillway gates will be diverted at downstream of the Dam to the Fulertal Barrage leaving little share of the water flow for Bangladesh. Hence there will be reduction in water flow for Bangladesh. Only very unusual and heavy rainfalls uncontainable and unmanageable at the reservoir up the Dam also imposing at the Fulertal Barrage a threat towards floods, an increase water flow will be released towards Bangladesh causing havocs of floods.
Post-monsoon period: Depending upon rainfalls, manageability of water level at the Dam as well as that at the Barrage, our wetlands of the Surma/Kushiyara Basin may be exempted from excess water i.e. no water-holds thus enabling early cultivation. However, unnatural and heavy rainfalls may reverse the situation and cause formation of water-holds in the haor areas.
Winter period: Heavy withdrawal upstream for the Fulertal Barrage may leave little or nothing for Bangladesh at the downstream. Literally, 1/3 Bangladesh is likely to go under the process of desertification ensuing a total collapse for 1/3 of Bangladesh.
Adverse effects upon various areas and disciplines like agriculture, fisheries, water resources, navigability, ground water level, livelihood etc. have been highlighted earlier. These will need minor adjustments here and there for different scenarios mentioned above.
Generation of Hydropower: The capacity designed is 1500 MW @ 80 per cent = 1200 MW (assumed). But the proposed firm generation set at only 412 MW is more intriguing.
Of the expected generation of 412 MW, Manipur has been offered 40 MW free to appease the people there. Thereafter how much India can afford to sell to Bangladesh and at what price, inclusive of the installation of transmission line up to the border and absorption of its cost in the price, needs to be looked at with a grain of salt.
Abdul Mannan is a former lawmaker and state minister for civil aviation and tourism
http://www.newagebd.com/2009/jun/29/oped.html
